Safety latch for automobile lifts



Oct. 20, 1931. c. J. BRISTOL 1,827,966

SAFETY vLATCH FOR AUTOMOBILE LIFTS I 'Filed sept. 23, 1929 Patented Oct. 20, 1931 i UNITED? cYnUs J. BBIsroL-or 'Das MOINES, Iowa,V Assenoa tro G'IioBEfivLacHi-NERY a `sum-LY compenser, or nnsnomns, Iowa, EA conronATIo-N or IOWA. Y

vSAFETY',` LATCH FOR AuTo'MoBILn rams l Application 'led September Therehas vrecently gone into cluite eXtensive use a type of automobile lifts for use at with a' piston `movablymounted thereinand l having a track atv the top to receive the automobile wheels. `The pistons are usually elel view through the upper portion of a cylinder K vated by o'ilbelow the piston and within the cylinder, which loilis actuated by air under pressure with which service Vstations are generally equipped for tire inflating"purposesV and the like. ,'In connection with y type.k it sometimes happens that the oil for supporting the piston in vits elevated position may1 :leal: out `and permit the pist-on to lower, and thismightresult in'injury to an operator working on the under si'deof an automobile carried bv the lift device. ,Y c

The object or myfinvention-isto provide an automatic safety latch 'device' of simple, *durable and inexpensive construction to ybe applied to the pistons for these'lifts, and which is so arranged'that when the piston'is in its elevated position-it cannot be lowered, even though VVall the oilf'below the piston should leak out, until theniston is again! elevatedy. which cany Olllyhegdone by havingthe space'below the pistonfilledl with oil, and then the operator manu-ally operatesa latch device for withdrawingthe latch topermit the low,-l

ering of 4the pistongand Further in this connectidn it is object to., provide a latch device of `thisLcharacter which will automatically be released as soon f n l y `The `flange 1s firmly secured to the cylinderas the slide bolts havepassed below the top of the cylinder, so that inftheevent that'lth'e piston is lowered only a slight degree orfthe ventire V,distance below -its Y elevated position andagain raised, thelatch device will prevent its downward movementI until such time' as the latch is' again manually,v released.

My invention consists in the construction, v

arrangement andcombinationjof myf im,-

proved latchdevice and itsV applicationtoa piston "and cylinder of the-r` character' 'de-y scribed, whereby the objects contemplated are attained, as hereinafter more fully set forth', v

pointed ,out in myclaiinspand illustrated in ,the accompanying .drawinssynfwhifli K, fof" this generalV 2a, 11929;Y .Sanarica/4,459;

v "Figure 1f showsr a side "elevation partly in section illustrating a piston and cylinder of thecharacter to which my improvement is and piston` having my improved latch device applied thereto, and shown by solid lines in position vorflcclring the piston against 'down-` wardmovement. In,l this ligure there is shown' by dotted linesvthelatch actuating de- Y l i yvice in position ,for holding the latch'in its withdrawn position, iand alsin the lower e portion ofthe figure I have illustrated by Vdotted lines the 'position'of the" latch device ,when it has passed belowthe top Idof the cyly meer and',

has beenmoved to its extended ,poyli`iguref?) shows an: enlarged, detail view showing a portion `ofth'eipiston and cylinder ,withmy improved latchi device therein,y the y latch ybeing sfhvown'in position where it has 1 v `been released bythe inwardmovement ofthe a Y n Y yslide b oltgandf v Figure' 4 showsasectional view onzthe line or FigureQ,V

top edge preferably formed with a rib 12.

`Vby theboltsl. The piston is indicated -gencrally by the numeral 14 andkhas a packing 15 at its lowerend to fitthe interior ofthe y cylinder and to prevent oil from passing upwardly beyond it. Y Y,

The liange l1 formsa guide forthe 4top of the pistonandthebody of the piston from the packing l5 upwardly stands spaced apart 'venting oil from. being transmitted from the interior-of the cylinder to the exterior of the piston, and hencethat' portion of the piston 1 whchprojects above the cylinder is 'always free frorn'oil.

Vfrom the interior of the cylinder, thus pre-l Mounted within the piston is a frame 16 vhaving a cross piece 17. Pivoted to this cross piece 17 are two arms, each composed of two parts 18. Between the parts of the lower end of each arm there is pivoted a slide bolt 19,

Y and this slide bolt is projected through and slidably mounted in an opening 20 in the cylinder 10. The upper portion of the slide bolt is beveled downwardly and Voutwardly at 21, and the lowerV portion of the outer end is Y beveled downwardly and inwardly at 22, for

purposes hereinafter made clear.

The upper ends of the arms 18 are con-` nected by contractile coil springs 23 yieldingly holding them toward eachother, and at the upper. end of each of the arms `18 there'is a pin24. I.

A latch plate 25 is mounted above the cross piece 17 with its lower end portion extending between the parts of the arms 18. VThis latch plate is fixed to a handle 26 which projects upwardly to a point above the hollow piston where it may be conveniently reached by an operator.V Y

engage and rest Aupon rib 12'surrounding the upper end ofthe cylinder, and when the device isin this position, angjoper'atormay freely work aroundan automobile supported on the lift device without any dangerof havingthe hlift device and automobile .move or fall downwardly, even though the oil which .l normally supports the .pistonin elevated Lposition shouldv leak out.

f IVhien vit is desired to lower the piston, the operator must first elevate the piston a slight distance, because normally ordinarily the weight of the automobile and lift upon the slide bolts resting upon the rib 12 is so great that the slide bolts cannot be withdrawnuntil this weight is removed from the slide bolts, and this can only be done by elevating the piston. i

After the piston has been elevated? aslight V.distancetthen the operator pulls upwardly uponthe handle2G.` This moves the latch plate 25 upwardly and therengagement of the v inclined edges 27thereofforce the pins 24 outwardly, thereby withdrawing the' 'slide bolts 19 inwardly, and this movement continues y until the pins 24: entier the notches 28, where-V upon the parts are locked in this position, and

The latch plate-25 has its sideledges in-VL this position is `indicated by dotted lines at the upper portion of Fi re 2.

Attention is called to the fact that when the slide bolts are'in this partially withdrawn position, the inclined portions 22 of the slide bolts are directlyabove the ribv 12.

When this operation has been performed, the operator may release the handle 26 and then by permitting the escape of air,`the oil in the cylinder is lowered andthe piston may move downwardly. Y When the slide bolts 19 engage the rib 12, then on account of this engagement, and onaccount of the inclined surfaces 22 of the slide bolts, the slide bolts are automatically moved inwardly, and this inward movement ofthe slide bolts releases the pins2l from their engagement in thenotches 28, whereupon the latch plate`25 moves downwardly by gravity until it rests upon the cross piece 17 whereupon the slide bolts 19 arelfree to be moved outwardly by the springs 23.

,In'ftheevent that after the piston hasmoved downwardly to position with the slide bolts 19below the top of-the cylinder,the operator should again apply air pressure to the device and raise the piston, then the slidebolts 19 will, as soon `as they get above the rib `12, move outwardly to position for again locking the piston in its upright position without any attention on the `part of the operator. 4

`From the foregoing-it will he seen that I `have provided` a `manually operatedV means for locking the slide bolts in a withdrawn position to permit the piston.to.move downwardly `(within thecylinden and that this manually operated means can be actuated only when the slide bolts are above and out of contact with the r upper portionV of the cylinder, and the only manner in whichthe .piston can be so ,positioned is when there is oil under pressure below thepiston. y.

Y It will also be seenthat I have provided a means actuated by downward movement of the piston for automatically repaleasing the slide bolts from their. withdrawn position, so that in the event 'that after the slide bolts `have passed below the rib '12,the`operator should again` raise theA piston, the slide bolts will automatically assume their locked. position without any attention whatever on` the 'part of the operator.

- In the event that when the piston is at the.

bottom of the cylinder, an operator should `move thellatch plate 25 upwardly, and'therevby lockthe slide boltsin their partially withdrawn position, then when the piston is elevated the inclined portions 21'of theV slide bolts will engage the lower edges ofthe flange 111, andthereby move the upper `ends of the arms l8`outwardly so that the pins' 24 release from thenotches 28, and itheflatchplate 25 will thendrop by gravity toy position for releasing the slide bolts.

By placing my: improved latch device within the interior of the hollow cylinder near combination of an upright cylinder, a piston y j l. In a device of the class-described, the

its lower end, and by extending the handle'l for operating it up through the hollow cylinder, I haveprovided a very convenient and] inexpensive structure in which the vparts arev l allV prevented from accidental movement or injury. n

I claim as my invention:

movable withinthe cylinder, a spring'actul' ated slide bolt carried by the piston and yieldits withdrawn position, said means includ-` c Y y ing a beveled portion on the slide boltyposi- 5 1 ingly held in an extended position to engage the vtop lof the cylinder and `prevent down-VV ward movement of the piston, manually operated means for locking the'slide bolt in aV withdrawn position to permit the .piston to j move downwardly within the cylinder, means' actuated by the movement of the piston for automatically releasing the slide bolt from ported within vthe piston, a slide bolt carried l by each arm and projected through the piston to engage the top of the cylinder,each

slide bolt having itsouter end at theupper portion thereof beveled downwardly and out- Y `wardly, Vand at the lower portion thereof' l beveledfdownwardlyand inwardly, a spring fory normallyholding the arms in positionVlr f for-moving the slide bolts to their projected j positions, al manually operated locking device yfor vmoving the slide bolts to a partially withdrawn position where the inclinedportions at thev lower ysides of the slide bolts will vengage the inner top edge of the cylinder to therebyv further withdraw the slide bolts when the piston moves downy through thetop Vof the cylinder, and means actuated f by-said inward movement ofthe slide bolts for releasing said locking device.

l 5. In a device of the class'described, the

combination of an upright cylinder, a piston movable within the cylinder, a slide bolt carried v by the piston .and yieldingly held in.

an extended position to engage the top of the lcylinder ,andV preventl downward movement of thepiston, manually operated means for locking the slidebolt in a withdrawn 'position to permit the piston to move vdownwardly within the cylinder, andv means actuated bythe movement of the piston for auto-v `matically releasing the r.slide bolt from its withdrawn position.

tioned tov co-operate with the top ofthe cyl- Y inder when the piston is moving downwardly with the position. Y

3. In a device ofthe class described.l. the

combination of an upright cylinder, agpiston lslide bolt" in its said withdrawn movable within the cylinder, two arms pivotally supported within the piston, 'a l slide bolt carried by each arm and projecting through thepiston to engage the top of the cylinder, each slide bolt having its outerend at the upper portion'thereof beveled downwardly and outwardly, and at the lower portion thereof beveled downwardly and inwardly, a spring for normally holding-thearms in position for moving the slide bolts to their projected positions, a manually operated r locking device for moving the slidebolts to a: partially withdrawnposition where the inclined portions at the lowersides 4of the i slide boltswill engage the inner top edge of the cylinder to thereby further withdraw the slide boltsv when the piston moves down through the top of the cylinder, and means actuated by said inward movement` of the slide bolts for releasing said locking device.

` 4. In a device of the'class described, the!` combination of an upright cylinder, avflange` ly, a piston movable within thefcylinder and at the ltop ofthe cylinder projected inwardengaging said flange, two armspivo'tallysup- 1 crans' J. BRISTOL. 

